Programmable integrated circuits are a type of integrated circuit that can be configured by a user to implement custom logic functions. In a typical scenario, a logic designer uses computer-aided design (CAD) tools to design a custom logic circuit. When the design process is complete, the CAD tools generate configuration data. The configuration data is loaded into a programmable integrated circuit to configure the device to perform desired logic functions.
Integrated circuits such as programmable integrated circuits and dedicated integrated circuits can be susceptible to temporary errors such as those caused by background radiation. For example, a charged particle in the environment that impacts circuitry on an integrated circuit can cause temporary malfunction of the circuitry (e.g., a flipped storage bit, a glitch on a signal path, etc.). Such temporary errors are sometimes referred to as soft errors or single event upsets (SEUs). Soft errors can be particularly disruptive for programmable integrated circuits. For example, configuration data loaded into a programmable integrated circuit may be corrupted by soft errors.
Circuitry such as transistors often degrade in performance and reliability over time in a process referred to as aging. Degradation over time may be caused by stress of transistors being held in on-states for extended periods of time or the frequency to which transistors are switched (as examples).
Techniques for improving the resiliency of an integrated circuit chip against soft errors include physical hardening of the chip (e.g., by using a radiation-resistant manufacturing or fabrication process) and logical hardening of the chip (e.g., by introducing redundancy and error correction). However, radiation hardening incurs significant cost to each radiation-hardened chip. For example, improving radiation resiliency by a factor of two may incur a die area cost of five percent or more. As another example, improving radiation resiliency by a factor of ten may increase per-device cost by thirty to forty percent. Resiliency may also be improved by periodically testing and repairing configuration data of a programmable integrated circuit.
With continuing migration to smaller process geometries, integrated circuit capacities continue to increase (e.g., the number of transistors and other circuit elements in each device increases). With increased integrated circuit capacities, the probability of device failure due to soft errors increases. However, improving the resiliency of devices to satisfactory levels may incur unacceptable amounts of cost. It would therefore be desirable to provide electronic devices with improved radiation resiliency.